Replacement for the core DNS module, includes server implementation

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0.7.09 years ago12 years agoMinified + gzip package size for native-dns in KB


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native-dns -- A replacement DNS stack for node.js


npm install native-dns and then var dns = require('native-dns');


native-dns exports what should be a 1:1 mapping of the upstream node.js dns module. That is to say if it's listed in the docs it should behave similarly. If it doesn't please file an issue


Beyond matching the upstream module, native-dns also provides a method for customizing queries.
var dns = require('../dns'),
  util = require('util');

var question = dns.Question({
  name: '',
  type: 'A',

var start =;

var req = dns.Request({
  question: question,
  server: { address: '', port: 53, type: 'udp' },
  timeout: 1000,

req.on('timeout', function () {
  console.log('Timeout in making request');

req.on('message', function (err, answer) {
  answer.answer.forEach(function (a) {

req.on('end', function () {
  var delta = ( - start;
  console.log('Finished processing request: ' + delta.toString() + 'ms');


Request creation takes an object with the following fields
question -- an instance of Question (required) server -- defines the remote end point (required) - as an object it should be
* `address` -- a string ip address (required)
* `port` -- a number for the remote port (optional, default 53)
* `type` -- a string indicating `udp` or `tcp` (optional, default `udp`)
You do not need to indicate ipv4 or ipv6, the backend will handle that - a string ip address timeout -- a number in milliseconds indicating how long to wait for the request to finish. (optional, default 4000) try_edns -- a boolean indicating whether to use an EDNSPacket (optional) cache -- can be false to disable caching, or implement the cache model, or an instance of Cache but with a different store (optional, default platform.cache)
There are only two methods
send -- sends the actual request to the remote endpoint cancel -- cancels the request and ignores any responses
Request emits the following events
message -- This is where you get a response, passes (err, answer) where answer is an instance of Packet timeout -- Fired when the timeout is reached cancelled -- Fired if the request is cancelled end -- Always fired after a request finished, regardless of disposition


If you want to customize all resolve or lookups with the replacement client stack you can modify the platform settings accessible in the top level platform object.
reload -- Re-read system configuration files to populate name servers and hosts
ready -- Boolean whether requests are safe to transit, true after hosts and name servers are filled watching -- Boolean indicating if system configuration files are watched for changes, default to false (currently can only be enabled on !win32) name_servers -- An array of servers used for resolving queries against - Each entry is an object of { address: <string ip>, port: 53 } - On win32 this is hard coded to be google dns until there's a sane way to get the data search_path -- An array of domains to try and append after a failed lookup attempts -- The number of retries for a failed lookup/timeout (default: 5) timeout -- The time each query is allowed to take before trying another server. (in milliseconds, default: 5000 (5 seconds)) edns -- Whether to try and send edns queries first (default: false) cache -- The system wide cache used by default for lookup and resolve, set this to false to disable caching
ready -- Emitted after hosts and name servers have been loaded unready -- Emitted when hosts and name servers configuration is being reloaded.


There is also a rudimentary server implementation
var dns = require('../dns'),
  server = dns.createServer();

server.on('request', function (request, response) {
    name: request.question[0].name,
    address: '',
    ttl: 600,
    name: request.question[0].name,
    address: '',
    ttl: 600,
    name: '',
    address: '',
    ttl: 600,

server.on('error', function (err, buff, req, res) {


Server creation
createServer and createUDPServer -- both create a UDP based server, they accept an optional object for configuration, - { dgram_type: 'udp4' } is the default option, the other is udp6 createTCPServer -- creates a TCP based server
Server methods
serve(port, [address]) -- specify which port and optional address to listen on close() -- stop the server/close sockets.
Server events
listening -- emitted when underlying socket is listening close -- emitted when the underlying socket is closed request -- emitted when a dns message is received, and the packet was successfully unpacked, passes (request, response) - Both request and response are instances of Packet when you're finished creating the response, you merely need to call .send() and the packet will DoTheRightThing error -- emitted when unable to properly unpack the packet, passed (err, msg, response) socketError -- remap of the underlying socket for the server, passes (err, socket)


header - id -- request id - qdcount -- the number of questions (inferred from array size) - ancount -- the number of questions (inferred from array size) - nscount -- the number of questions (inferred from array size) - arcount -- the number of questions (inferred from array size) - qr -- is a query response - opcode - aa -- Authoritative Answer - tc -- Truncation bit - rd -- Recursion Desired - ra -- Recursion Available - res1 -- Reserved field - res2 -- Reserved field - res3 -- Reserved field - rcode -- Response Code (see consts.NAME_TO_RCODE) question -- array of Questions answer -- array of ResourceRecords authority -- array of ResourceRecords additional -- array of ResourceRecords
send() -- Handles sending the packet to the right end point


A Question is instantiated by passing an object like:
name -- i.e. '' (required) type -- Either the string representation of the record type, or the integer value, see consts.NAME_TO_QTYPE (default: 'A') class -- The class of service, default to 1 meaning internet


ResourceRecords are what populate answer, authority, and additional. This is a generic type, and each derived type inherits the following properties:
name -- The name of the resource type -- The numerical representation of the resource record type class -- The numerical representation of the class of service (usually 1 for internet) ttl -- The Time To Live for the record, in seconds
Available Types:
SOA - primary -- string - admin -- string - serial -- number - refresh -- number - retry -- number - expiration -- number - minimum -- number A and AAAA - address -- string MX - priority -- number - exchange -- string TXT - data -- string SRV - priority -- number - weight -- number - port -- number - target -- string NS - data -- string CNAME - data -- string PTR - data -- string NAPTR - order -- number - preference -- number - flags -- string - service -- string - regexp -- string - replacement -- string